package com.finesys.backend.common.utils;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import com.google.common.base.Charsets;
import com.google.common.hash.Hashing;


public class MD5Tools {

    // 十六进制下数字到字符的映射数组
    private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d",
            "e", "f" };

    /**
     * 对字符串进行加密
     * 
     * @param txt
     * @return
     */
    public static String encode(String txt) {
        try {
           // return encodeByMD5(encodeByMD5(encodeByMD5(txt) + txt) + txt);
        	return Hashing.md5().newHasher().putString(txt, Charsets.UTF_8).hash().toString();
        } catch (Exception ex) {
            return null;
        }
    }

    /**
     * 对字符串进行MD5加密
     * 
     * @throws NoSuchAlgorithmException
     */
    private static String encodeByMD5(String originString) throws NoSuchAlgorithmException {
        if (originString != null) {
            // 创建具有指定算法名称的信息摘要
            MessageDigest md = MessageDigest.getInstance("MD5");
            // 使用指定的字节数组对摘要进行最后更新，然后完成摘要计算
            byte[] results = md.digest(originString.getBytes());
            // 将得到的字节数组变成字符串返回
            String resultString = byteArrayToHexString(results);
            return resultString;
        }
        return null;
    }

    /**
     * 转换字节数组为十六进制字符串
     * 
     * @param b 字节数组
     * @return 十六进制字符串
     */
    private static String byteArrayToHexString(byte[] b) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++) {
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }

    /** 将一个字节转化成十六进制形式的字符串 */
    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n = 256 + n;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

/*    public static void main(String[] args) throws NoSuchAlgorithmException {
        System.out.println("对 用MD5摘要后的字符串：" + "1");
        String password = MD5Tools.encode("1");
        System.out.println("对 用MD5摘要后的字符串：" + password);
  
    }*/

    
}
